Enhanced electrochemical performance of silicon monoxide anode materials prompted by germanium

Abstract

Abstract Although silicon oxide (SiO) as an anode material shows significant potential for application in lithium-ion batteries (LIBs) due to its high capacity, low cost, abundance, and adequate safety characteristics, severe capacity decay and sluggish charge transfer during discharge-charge processes limit its application. Herein, a novel strategy for preparing a ternary SiO@Pc@Ge composite has been developed using self-assembly via freeze drying and thermal melting. A robust and interconnected SiO@Pc frame provides sufficient channels for charge transfer and adequate number of pores for electrolyte infiltration. The in-situ assembled Ge nanoparticles are evenly dispersed in the SiO@Pc matrix like sesame seeds, augmenting the electrochemical activity of SiO. The SiO@Pc@Ge composite with a significant mass ratio delivers a high discharge capacity of 980.5 mA h g-1 in the initial 100 cycles at 100 mA g-1 and an excellent capacity retention of 90%, while exhibiting a superior rate capability of 627.8 mA h g-1 at 1400 mA g-1. Furthermore, the phase evolution and underlying Li storage mechanism during the charge-discharge process are further revealed via XPS and CV investigations, which indicate that the Li-ion kinetics is enhanced in the optimized samples. Our method provides novel insights into the utilization of low-cost and environmentally benign materials for fabricating high-performance energy devices through a simple and feasible procedure.